The present invention relates in particular to a system for testing an electronic system that comprises a plurality of pieces of electronic equipment together with one or more interconnection structures interconnecting said pieces of equipment.
The invention applies in particular when interconnection is performed by one or more communications buses and/or links that is/are implemented to comply with one or more standards taken from the following: MIL-STD-1553 (A or B); STANAG 3350; STANAG 3838; STANAG 3910; ARINC 429; ARINC 453; ARINC 629; ARINC 636; MIL-STD-1773; AFDX; ASCB; CSDB; IEEE P1014; RS232; RS422; RS485.
Electronic systems on board aircraft and rotorcraft generally include a plurality of computers connected in particular to sensors, to actuators, and to displays.
Testing such systems for proper operation is complex and lengthy, and is consequently expensive.
It is difficult to prepare and carry out such tests, in particular because of the large amount of signals and data that are exchanged by the pieces of equipment while they are in operation, and because of the large number of possible configurations for the pieces of equipment constituting the electronic system, e.g. depending on whether the electronic system is designed for fitting to an aircraft having no weapons system, or on the contrary for fitting to an aircraft having a weapons system.
Patent EP-0 532 017 describes a test system for electronic equipment, the test system comprising a generic test controller GTC together with a functional interface unit FIU that is specific to a particular weapons system, each connected to an interface panel with apparatuses under test and communicating via an IEEE-488 bus. The generic controller GTC and the specific unit FIU are each connected to analog and digital input/output (I/O) cards or instruments via an IEEE-796 bus. The GTC controller has interface cards with the 1553 bus that are capable of operating as bus controllers, as terminals, or as a bus monitor. Test programs can be modified and compiled by a central computer via an RS232 link, and recorded on a storage unit that is connected to the microprocessor unit of the GTC controller, as in an operator interface.
Patent EP-0 827 608 describes a method of testing electrical circuits in which the test program is split into an element relating to the test sequence that calls on data contained in a test data field, and an element relating to controlling the test device.
Patent EP-0 985 155 describes a test method in which an operator inputs information to define a command sequence for application to a test device connected to a piece of equipment for testing. For each command of the command sequence, the operator inputs a command number, a command type, parameters or variables for the command, and an expected result for the test corresponding to said command. To do this, the operator is assisted both by a dictionary of the various types of commands that are applicable to the equipment for testing, and also by a database combining the variables contained in the arguments of the commands and the values that each variable can take. Thereafter, the operator can cause the input command(s) to be executed by the test device and can archive the test results. The test device can undertake analysis to verify that a command type as input is to be found in the dictionary, that the arguments present a syntax that corresponds to that in the dictionary, and that the variables as input are to be found in the variables database.
Patent EP-1 583 289 describes a system for simulating and testing an AFDX network that can be used for simulating one or more pieces of equipment using “off-the-shelf” equipment.
Known methods and systems for simulation and/or testing are generally designed to test a narrow range of pieces of equipment.
The purpose of testing an on-board electronics system (avionics system) is to verify that the functions allocated to the system are indeed fulfilled. These functions are generally defined in informal manner. From such a definition, a human being, a test operator, can generate a command sequence for a test device (or “test bench”), e.g. as described in patent EP-0 985 155.
Given the complexity of the system for testing, a complete sequence of commands that is sufficient for testing a determined function of the system can comprise one or more thousands of commands.
Generating command sequences for applying to the test apparatus requires the skills of a highly-qualified human operator. Because of the wide variety of the pieces of equipment that form part of an avionics system, it is difficult if not impossible to find an operator who is fully qualified for all of the kinds of equipment in the system and for all of the functions that the system as a whole is called on to perform. It is therefore generally necessary to rely on a plurality of operators selected for their high levels of qualification but each concerning some only of the pieces of equipment and/or the functions to be tested.
Developing an on-board electronics system often requires testing of the suitability of the system to perform some determined function to be performed successively on several occasions.
In particular because of the informal nature of the definition of a function that is to be performed by such an electronics system, it is quite possible for two distinct operators to produce two different sequences of commands, and for the execution of those two sequences of commands to produce different test reports.
In addition, for a given command, two distinct operators may select two distinct values for such-and-such a parameter or variable of that command, thereby likewise producing two different test reports. Comparing such test reports can be meaningless or can lead to a wrong conclusion.